|
•
<br />Issues
<br />A number of issues were raised and discussed at the MANWAC meetings concerning airboat use of the St.
<br />Sebastian River, and whether or not it is appropriate for the County to adopt an ordinance restricting airboats
<br />in the river. A summary of the issues is as follows:
<br />• Is enforcement of existing regulations (i.e., slow speed zones, noise regulations) sufficient
<br />to address the concerns of airboat use on the St. Sebastian River?
<br />• Is there empirical evidence that airboats adversely affect wildlife, are a noise nuisance, and
<br />are a safety concern on the St. Sebastian River, distinguished from other types of boats, such
<br />that it justifies a specific prohibition of airboats vs. other types of boats on the river?
<br />• Does the County have the authority to regulate airboats (or other boats) on the St Sebastian
<br />River?
<br />• Should the County consider other alternatives, such as prohibiting all types of motor driven
<br />boats on portions of (or all of) the river, or prohibit all boats over a certain size or with
<br />motors over a certain horsepower on portions of the river.
<br />These issues are discussed and explored in the analysis section of this memorandum.
<br />Legal Authority
<br />According to Sections 327.22 and 327.60, Florida Statutes, local governments have the authority to regulate
<br />vessels in accordance with specific conditions (see the attached memorandum dated April 30, 1998, from
<br />Deputy County Attorney Will Collins). Existing speed zone regulations are enforced by the Sheriffs -Office,
<br />Florida Marine Patrol TMP) and the Florida Game and Freshwater Fish Commission (GFC). The U.S. Coast
<br />Guard is responsible for certifying watercraft, and enforcing federal safety and operating regulations.
<br />Florida Statutes restrict noise associated with vessels to 90 decibels, measured 50 feet from the source.
<br />According to county attorney staff Florida Statutes preempt local governments from adopting stricter decibel
<br />level prolubitions. County staff the Florida Marine Patrol, and the County Sheriff's Department have
<br />attempted to monitor the Wilderness AkWat Tours business to determine if violations of the 90 decibel level
<br />have occurred. However, no violations of the 90 decibel threshold have been documented by these agencies
<br />to date.
<br />According to county attorney staff~ for local government restrictions to be defensible in court, the restrictions
<br />must serve a legitimate public purpose, and must be structured as narrowly as possible to serve the intended
<br />purpose. Therefore, if the County is to adopt restrictions affecting use of the St Sebastian River, the scope
<br />of the restrictions must be justified as the minimum necessary to serve the specific public purpose.
<br />Noise Nuisance
<br />The main complaints received by county staff relate to noise associated with airboat usage of the St
<br />Sebastian River. As discussed at the MANWAC meetings, noise complaints arose when tour business
<br />airboats operated at higher than slow speed, or when the airboats' engines were gunned for the vessels to
<br />negotiate tums, particularly in windy conditions. It was discussed at the MANWAC meetings that the main
<br />source of the noise, rather than the engine itself, is the propeller cutting the air at high speed.
<br />According to airboat manufacturers, an airboat is capable of producing noise up to 120 decibels (a sound
<br />similar to a siren at 10 feet) when operated at full throttle, as heard by the airboat operator. Most airboat
<br />noise is attributed to the fan or blade. According to the Florida Marine Patrol, when an airboat is operated
<br />at slow speed and with the proper sound reducing equipment installed, it makes noise similar to that of a boat
<br />with an outboard marine engine.
<br />Indian River County's Noise Ordinance (Chapter 974 of the County Code) limits peak noise levels in
<br />residential zoning districts to 80 dBA (A -Scale decibels), and to 75 dBA in conservation zoning districts
<br />(which applies to the St Sebastian River Buffer Preserve, on the west side of the river). Sound of a longer
<br />duration (i.e., 7'/z minutes at a time) is limited to 60 dBA and 55 dBA, respectively. However, because the
<br />State preempts local governments from setting noise limits lower than 90 dBA, the County ordinance levels
<br />are unenforceable with regard to airboats (and other boats) on the river. Therefore, although the county may
<br />receive complaints of noise nuisance associated with airboats on the river, the County is legally constrained
<br />from taking enforcement action, unless the 90 dBA threshold is breeched, which has yet to be documented
<br />Wildlife Impacts
<br />Residents who live along the St. Sebastian River have expressed concems that the airboat tour business is
<br />having a detrimental effect on wildlife associated with the river. The concerns relate to noise and "prop
<br />wash" impacts to wildlife. However, these claims has not been substantiated County staff has searched the
<br />Internet for information on noise impacts to wildlife. Most studies found related to aircraft noise as it affects
<br />wildlife at national parks. The general conclusion is that noise impacts vary among wildlife species
<br />depending upon such factors as temperament, sex, age and prior experience with noise; time of year (e.g.,
<br />nesting season); and whether other physical stressors (e.g., drought, habitat depletion) are present Other
<br />variables include the level and duration of the noise in question. Concerning impacts to manatees, which
<br />frequent the St Sebastian River, there is no justification to distinguish airboats from other types of boats
<br />regarding potential impacts to manatees.
<br />JUNE 211998
<br />
|